Recently, an ultrasound system has been extensively used in the medical field due to its non-invasive and non-destructive nature. Modern high-performance ultrasound imaging systems and techniques are commonly used to produce two dimensional ultrasound images and three-dimensional ultrasound images of internal features of patients.
Generally, the ultrasound image is displayed in a Brightness-mode (B-mode) by using reflectivity caused by an acoustic impedance difference between the tissues of the target object. However, if the reflectivity of the target object is hardly different from those of the neighboring tissues such as tumor, cancer or the like, then it is not easy to recognize the target object in the B-mode image.
When the target object is a blood vessel, an intravascular ultrasound imaging method is adopted to diagnose a lipid or lesion positioned at an inside of the blood vessel. In such a case, a probe is inserted into the inside of the blood vessel to form an ultrasound image of the blood vessel. Although a high resolution of the ultrasound image of the blood vessel may be obtained through the intravascular ultrasound imaging method, there is a problem in that the blood vessel may be damaged.